The commission says cities’ nighttime closures are illegal without state approval. The first big fight is shaping up in Los Angeles, which says the panel has little authority over local statutes.

The California Coastal Commission is taking aim at beach curfews established by cities up and down the coast, saying they are illegal without state approval and that people have a right to be on the sand whenever they want.

The first major battle is brewing in Los Angeles, where the coastal agency has told the city that its longstanding midnight-to-5 a.m. curfew barring the public from beaches, piers and oceanfront parks from Will Rogers State Beach to Cabrillo Beach violates the state Coastal Act and must be relaxed.

Coastal Commission Executive Director Peter Douglas said he’d like to forge compromises with Los Angeles and other cities for narrower curfews that would extend beach hours and grant exceptions for recreational activities while addressing proven public safety concerns. Already, Laguna Beach has changed its curfew rules since the commission raised objections.

“There are a lot of people who want to use the beach, which they have a constitutional right to do, in the middle of the night,” Douglas said. “You don’t preclude the public from that use without a good justification — a good reason — and we have to be able to look at that.”

The new push is likely to renew debate over coastal access, with beach cities arguing that the curfews are needed to ward off late-night crime on the sand. Coastal Commission officials argue that crime has dropped significantly in the last decade while demand for time on the beach has increased.